San Francisco remains mostly cool despite heat wave
On Friday, while inland Bay Area cities scorch under near-triple-digit heat, San Francisco will largely escape the intensity thanks to the persistent marine layer. Neighborhoods west of Twin Peaks, including the Sunset and Richmond Districts, will remain in the 60s °F (16–20 °C), while Mission, SoMa, Bayview, and Portola will feel warmer air, with highs in the mid-70s °F (24–25 °C).
Downtown San Francisco could briefly touch 75 °F (24 °C) Friday afternoon before the sea breeze kicks in by evening, dropping temperatures to around 60 °F (16 °C). North Beach and other coastal neighborhoods might struggle to even reach 65 °F (18 °C) due to lingering fog and cool ocean winds. Overnight lows will settle in the mid-50s °F (12–13 °C).
Coastal areas hold steady, inland areas boil
While Oakland, Berkeley, and Alameda might see highs in the upper 70s to low 80s °F (25–28 °C), communities east of the Caldecott Tunnel like Walnut Creek and Pleasanton are expected to climb into the mid-90s to low 100s °F (35–38 °C).
Farther inland, Antioch and Brentwood may touch 100 °F (38 °C) for the first time this year — weeks earlier than usual. Meanwhile, Vallejo, Petaluma, and Western Marin will remain much cooler, with highs in the 60s to upper 80s °F (16–31 °C), depending on their proximity to the coast.
Santa Clara Valley and South Bay under heat advisory
From 11 a.m. Friday, a heat advisory is in effect for the Santa Clara Valley and Santa Cruz Mountains, where temperatures will soar into the mid-90s to 100 °F (35–38 °C). Morgan Hill and Gilroy are most likely to hit the century mark, while San Jose, Santa Clara, and Milpitas stay slightly cooler, in the 90s °F (32–35 °C).
In contrast, Santa Cruz and coastal areas will feel relatively mild, with temperatures in the upper 70s to low 80s °F (25–27 °C). Overnight lows in the mountains will hover in the low to mid-60s °F (16–18 °C).
Saturday’s weather will echo Friday’s pattern
On Saturday, expect another hot day inland, but with slightly stronger sea breezes keeping coastal cities cooler. San Francisco will again see 60s to 70s °F (16–25 °C) depending on location, while Vacaville, Fairfield, and Brentwood could see highs reach 103 °F (39 °C). Meanwhile, Peninsula cities like San Mateo and Redwood City will still flirt with the 90s °F (32–33 °C).
The marine layer will deepen, helping moderate the heat a bit, but inland valleys will remain well above average for late May.
Sunday brings relief across the Bay Area
By Sunday, a regional cooldown will drop temperatures by 10 to 15 degrees. Highs across the Bay shoreline will fall into the upper 60s to mid-70s °F (20–24 °C), and inland valleys will settle back to the mid-70s to mid-80s °F (24–29 °C). Westerly winds, gusting at 20 to 30 mph, will reinforce this cooling trend, particularly in San Francisco and along the coastline.
Expect a mix of sunshine and clouds, a refreshed breeze, and lower overnight temperatures — a significant shift from the brief but intense heatwave.
